Aircraft: CARAVAN UNDIFFERENTIATED
Phase of flight: Cruise
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT

Aircraft entered an MVA (Minimum Vectoring Altitude) of 10500 ft while at 10000 ft. I as Supervisor; was conducting training on approach control and a standalone CIC (Controller in Charge) was present. We had recently implemented STARS (New radar software) and I was sitting on the 'B' scope adjacent to the 'A' scope where training was being conducted. I was making new preference settings and watching from the 'B' scope. Additionally; I was familiarizing myself with some of the STARs features and suggesting alternate courses of action to the trainee regarding the expected arrival traffic.The trainee issued a 30 degree left turn which is a routine clearance for this aircraft and has always been safe because the 10500 ft MVA had not come into play for this aircraft prior to this event. Unfortunately; the aircraft was south of its normal route hence; closer to the 10500 ft MVA. I heard the trainee issued the climb but thought it was so he could tunnel a medevac aircraft underneath him. The MSAW (Minimum Safe Altitude Warning) did not activate and I was unaware that the aircraft entered the MVA too low. The trainee controller's shift ended and after he left work he called me back and advised me of the situation. That's when I became aware of it and filed a MOR (Mandatory Occurrence Report). I asked the controller in Charge what she remembered and she stated that she thought the aircraft had been climbed. I reviewed the radar replay and the aircraft was issued a climb prior to the MVA but the time was insufficient to clear the MVA.The trainee was getting close to certification and my attention to detail waned. The aircraft's route was further south than it typically is. The higher MVA had never been a factor prior to tonight for a 30 degree turn on this aircraft. At various times; the three controllers were discussing ATC questions and may have been distracted. I had been on Sick Leave earlier in the shift visiting a clinic. My shoulder was sore and my stomach was slightly upset. In fact; during this session I asked the CIC upstairs to send some Tylenol down the drop tube. It's possible that my ailments affected the performance of my duties. I'd also been on Flight Surgeon approved meds. One side effect of which is stomach issues.The trainee noticed the event at the time but did not advise myself or the CIC of the issue. I don't know why he didn't speak up. Fear of not getting certified? Lack of trust? It's possible that the situation could've been fixed. I asked him later why he didn't say anything at the time and he said he didn't know why. I encourage him to always say something in the future. The CIC is a new CIC; rated less than 2 weeks. Does a Supervisor in the room mean that others believe everything is under control when it may not be? Reiterate our Safety Culture to say something when you see it. Once again light traffic and distractions created a trap for three of us to step in. [Report narrative contained no additional information.] CPR TRACON Controller conducting training reported that undetected to him; a trainee vectored an aircraft below the Minimum Vectoring Altitude.